The 11-month tennis season lurches to a close at next week's Masters Cup with the world number one spot still up for grabs.

The crème de la crème of men's tennis will gather in Texas with the top eight players in the ATP Champions Race vying for a chunk of the $3.7 million purse.

But only American Andy Roddick, Juan Carlos Ferrero of Spain and Switzerland's Roger Federer can still grab the biggest prize -- the coveted number one world ranking.

Five players have occupied the top spot this season but it is Roddick who will take the honour into the Houston's West Side Tennis Club for the season finale after taking possession of it in Paris last week.

The climb to the tennis summit capped a dizzying 10 months for Roddick, who began the campaign ranked 10th in the world with many questioning if he could ever fulfill the promise predicted for him since he exploded onto the scene in 2000.

Roddick answered those questions with six titles, including his first Grand Slam at the U.S. Open, and now has the opportunity to underline his status with success at his first Masters Cup.

"[The Masters Cup] was one of my goals at the beginning of this year, because it means you've had consistent results for the whole year," said Roddick. "I've also had success in Houston and I'm looking forward to playing there again."

Texas has provided a happy hunting ground for the 21-year-old, who claimed what was his second career title last year in Houston and reached to the final of this year's event.

Like everything else, they like their tennis big and brash in Texas and Roddick, a fist-pumping, larger than life figure with a movie star girlfriend and booming serve fits the bill.

EXHAUSTING SEASON

Following an exhausting season, the support from the crowd should provide the American with a jolt of energy against some weary opponents.

Trailing Roddick by just 26 points in the title race, Ferrero is well within striking range of his American rival with 20 points on offer for each of three round robin matches, 40 for a semi-final win and a further 50 for the title.

The soft-spoken French Open champion knows the effort required, having made to last year's final in Shanghai before falling to Lleyton Hewitt.

But at the end of another long season, the Spaniard says he is nearly out of gas.

"I'm tired and I have to travel a lot before I finish the year," said Ferrero. "I've won a Grand Slam and have had good results this year. I've done well at the Masters Cup in Sydney and Shanghai, so I hope to continue that in Houston."

Federer has also made it to the year end showcase before, but the Wimbledon champion -- 142 points adrift of Roddick -- will need more luck than experience if he is to take the number one to Switzerland for the first time.

Half of the eight combatants -- Roddick (21), Ferrero (23), Federer (22) and Argentines Guillermo Coria (21) and David Nalbandian (21) -- are 23 or younger indicating something of a changing of the guard in men's tennis.

Germany's Rainer Schuettler and Spain's Carlos Moya, both 27, and Agassi complete the entry list.

A decade older than the majority of his competition, 33-year-old Agassi may well arrive in Houston with the most jump to his game.

The Australian Open champion will be returning to action for the first time since the U.S. Open, having taken a break following the birth of his daughter.